Cardiotomy reservoirs are used during major surgery to collect blood which has been accumulated in a surgical incision site or elsewhere by an air-driven cardiotomy sucker or the like.
It is very desirable to reinfuse this blood into the patient since a patient's own blood is far superior to any donated blood that he can receive. However, blood which has been removed from an incision site is likely to contain small clots and other forms of solid debris, which should not be reinfused into the patient.
Hence, blood is passed into the cardiotomy reservoir, where it passes through a filter to remove air bubbles and the undesirable solid debris, and where it can be stored under blood preserving conditions until the surgeon elects to return the blood to the patient, which is usually immediately after purification of the blood.
The prior art device of U.S. Pat. No. 3,507,395 is commercially available and widely used as a cardiotomy reservior. However, it has certain disadvantages which limit its effective use. First, the filter of the prior art reservoir is unsupported, and thus is subject to collapse under certain conditions of use. Also, the filter does not extend the entire length of the unit. Hence, air from cardiotomy suckers entering along with the blood into the reservoir must migrate through the filter, and may bubble through filtered blood prior to reaching the vent from which the air leaves the reservoir. This may initiate the formation of small bubbles in the filtered blood, and have other bad effects.
Similarly, any resupply of blood which is added to the prior art cardiotomy reservoirs in the conventional manner at the upper end thereof is not filtered prior to infusion to the patient. Hence, the small clots which may be present in resupply blood (which may come fresh from a blood bag or the like) are not removed prior to infusion.